<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>

      let world = 'hello world'
      let address = 'china'
      let obj = {
        name : 'zs',
        [world] : 'ls',   // hello world ： ls
        address           // assress : china
      }
      console.log(obj);  // 表达式键名


      let obj2 = {
        id : 1,
        name : 'zs'
      }
      // 直接替换 obj2 的内容，对象名不变，内容改变
      ['obj2.address'] = 'china'
      console.log(obj2);  // 打印 obj2 输出 china

    </script>
</body>
</html>